This is not really a bug.
The circuit system uses signed 32 bit integeres, so the limits follows, once the maximum positive number is 2 147 483 647 (which also happens to be a prime number, I had no idea https://en.wikipedia.org/wiki/2,147,483,647), similar limit is for negative numbers ...

I'm not sure if this is a bug but I thought I'd report anyway and let you guys decide.

What did you do? I have an outpost smelting facility (copper plate) that I have wired with green wire to provide its total (48 iron chest contents that is part of a train station) to another smelting facility ...